The Space Anomaly is a large round, metallic structure in No Man's Sky. It can be summoned from the Starship quick menu while in space, if the player has unlocked the option to do so by completing the main story missions.
Approaching the doors of a Space Anomaly will automatically guide a Starship inside, in the same way that a Space Station does. Priest Entity Nada and Specialist Polo are always found within the Space Anomaly, along with many other NPCs, some of which serve practical purposes.
Since the Beyond update the Space Anomaly has become a player hub that allows players to complete missions via The Nexus, alone or with other players, to gain quicksilver, Nanite Clusters, Units, and various valuable items. Players are able to interact with each other as they would outside the Space Anomaly.